JP2011229125A - Tuning-fork type piezoelectric vibration piece and piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tuning-fork type piezoelectric vibration piece which has groove portions formed in vibration arms, and a piezoelectric device using the piezoelectric vibration piece.SOLUTION: The tuning-fork type piezoelectric vibration piece 100 bonded in a package with a conductive adhesive includes a connection electrode electrically connected to the conductive adhesive, and a pair of vibration arms 12 extending from a base 11 made of a piezoelectric material in a predetermined direction and having excitation electrodes 53 electrically connected to the connection electrode formed thereon. Each of the vibration arms has a two-sided surface, being crossed at both sides of top and reverse surfaces, and also has a groove portion 23L or 23R, extending in the predetermined direction on the top and reverse surfaces respectively, the excitation electrodes have top and reverse electrodes 531R, 531L formed in the groove portions on the top and reverse surfaces respectively and side face electrodes 532R, 532L formed on the both side faces respectively, and the top and reverse electrodes have thinner film thicknesses than the connection electrode.

Description

  The present invention relates to a tuning fork type piezoelectric vibrating piece having a groove formed in a vibrating arm, and a piezoelectric device using the piezoelectric vibrating piece.

  For example, Patent Document 1 discloses a tuning fork type piezoelectric vibrating piece that lowers a CI (crystal impedance) value. The pair of vibrating arms of the tuning-fork type piezoelectric vibrating piece has excitation electrodes in grooves formed on the front and back surfaces. The pair of vibrating arms has excitation electrodes formed on the side surfaces. The tuning fork type piezoelectric vibrating piece of Patent Document 1 distinguishes these excitation electrodes into four regions in cross section, and adjusts the thicknesses of the four regions to reduce factors that hinder vibrations and reduce stress. The effect on the frequency is reduced. Further, the tuning fork type piezoelectric vibrating piece suppresses the CI value and reduces the influence on the frequency.

Japanese Patent Laid-Open No. 2003-178022

  Patent Document 1 does not disclose how to adjust the thickness of the excitation electrode, but it is difficult to adjust the thickness of the excitation electrode of the minute vibrating arm in each of the four regions.

  The present invention has been made in order to solve the above-described problems, and by simply adjusting the thickness of the excitation electrodes of a pair of vibrating arms, the piezoelectric vibrating piece that reduces the factor that hinders vibration and reduces the CI value. And it aims at providing a piezoelectric device.

  A tuning fork-type piezoelectric vibrating piece according to a first aspect is a tuning-fork type piezoelectric vibrating piece fixed by a conductive member in a package, and includes a connection electrode electrically connected to the conductive member, and a base made of a piezoelectric material. A pair of vibrating arms formed with excitation electrodes extending in a predetermined direction and electrically connected to the connection electrodes, the vibrating arms having front and back surfaces and both side surfaces intersecting on both sides of the front and back surfaces. Grooves extending in a predetermined direction are formed on the back surface, and the excitation electrodes have front and back electrodes formed in the groove portions on the front and back surfaces, and side electrodes formed on both side surfaces, respectively, The thickness is smaller than the thickness of the connection electrode.

  A tuning fork type piezoelectric vibrating piece according to a second aspect is the first aspect, wherein the connection electrode and the excitation electrode include a first layer formed on the piezoelectric material and a second layer formed on the first layer. The second layer of the front and back electrodes is thinner than the second layer of the connection electrode.

  In the tuning fork type piezoelectric vibrating piece of the third aspect, in the first aspect or the second aspect, the film thickness of the front and back electrodes is 20 to 90% of the film thickness of the connection electrode.

  In the tuning fork type piezoelectric vibrating piece according to the fourth aspect, the connection electrode is formed at the base in the first to third aspects.

  A tuning fork type piezoelectric vibrating piece according to a fifth aspect includes, in the first to third aspects, a pair of support arms extending in a predetermined direction from the base on both outer sides of the pair of vibration arms, and the connection electrode is formed of the support arm. It is formed at the tip.

  In the tuning fork type piezoelectric vibrating piece according to the sixth aspect, from the first aspect to the fifth aspect, the film thickness of the front and back electrodes is formed thin by etching with an inert gas, laser irradiation or metal etching.

  A tuning fork type piezoelectric vibrating piece according to a seventh aspect is a tuning fork type piezoelectric vibrating piece fixed in a package, extending in a predetermined direction from a base portion made of a piezoelectric material, and intersecting both sides of the front and back surfaces. A pair of vibrating arms, front and back electrodes formed on the front and back surfaces, and excitation electrodes having side electrodes formed on both side surfaces, respectively, and the film thickness of the side electrodes or the film thickness of the front and back electrodes Based on the data of the correspondence relationship with the peak temperature of the frequency temperature characteristic, the film thickness of the side electrode is adjusted so that the peak temperature of the frequency temperature characteristic becomes a desired temperature, and a step or rough surface is formed on the side electrode or the front and back electrodes. A tuning-fork type piezoelectric vibrating piece in which is formed.

  The tuning fork type piezoelectric vibrating piece according to the eighth aspect is the tuning fork type according to the seventh aspect, wherein the film thickness of the side electrode or the front and back electrodes is increased when the vertex temperature is higher than a desired temperature. Piezoelectric vibrating piece.

  The tuning-fork type piezoelectric vibrating piece according to the ninth aspect is the eighth aspect, wherein the film thickness of the side electrodes or the front and back electrodes is increased by sputtering or vacuum deposition.

  In the tuning fork type piezoelectric vibrating piece according to the tenth aspect, in the seventh aspect, when the vertex temperature is lower than a desired temperature, the thickness of the side electrode or the front and back electrodes is reduced.

  In the tenth aspect, the tuning-fork type piezoelectric vibrating piece according to the eleventh aspect is formed such that the thickness of the side electrode or the front and back electrodes is reduced by etching with an inert gas, laser irradiation, or metal etching.

  A tuning fork type piezoelectric vibrating piece according to a twelfth aspect is the seventh aspect to the eleventh aspect, wherein the excitation electrode includes a first layer formed on the piezoelectric material and a second layer formed on the first layer. The thickness of the second layer of the side electrode or the front and back electrodes is adjusted.

  A piezoelectric device according to a thirteenth aspect includes a tuning fork type piezoelectric vibrating piece according to the first aspect to a twelfth aspect and a package that houses the tuning fork type piezoelectric vibrating piece.

  INDUSTRIAL APPLICABILITY The present invention can provide a tuning fork type piezoelectric vibrating piece and a piezoelectric device that reduce the factor that hinders vibration and suppress the CI value.

FIG. 4A is a plan view of the first tuning-fork type piezoelectric vibrating piece 100. FIG. 2B is a cross-sectional view of the first tuning-fork type piezoelectric vibrating piece 100 in the BB cross section of FIG. FIG. 2C is a cross-sectional view of the first tuning-fork type piezoelectric vibrating piece 100 in the CC cross section of FIG. (A) is a graph showing the relationship between the CI value of the first tuning-fork type piezoelectric vibrating piece 100 and the thickness of the groove second layer / the thickness of the base second layer (F1 / F2). (B) is a graph showing the relationship between the CI value of the first tuning-fork type piezoelectric vibrating piece 100 and the film thickness of the side surface second layer 532 / the film thickness of the base second layer 51 (F4 / F2). (C) is a photograph of the right groove region 13R from which part of the groove second layer 531R has been removed by laser light irradiation. FIG. 6D is a cross-sectional view of the right groove region 13R in which the thickness of the second side layer 532R is increased by sputtering. (A) is a perspective view of the piezoelectric device 1000. FIG. (B) is sectional drawing of the piezoelectric device 1000 in the EE cross section of Fig.3 (a) and FIG.3 (c). (C) is sectional drawing of the piezoelectric device 1000 in the FF cross section of FIG.3 (b). 4 is a first flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. FIG. 4 is a second flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. FIG. (A) is a plan view of the piezoelectric material wafer 150 on which the first tuning-fork type piezoelectric vibrating piece 100 is formed. FIG. 4B is a diagram showing an enlarged portion 160 of the piezoelectric material wafer 150. FIG. (A) is the figure which expanded a part of 1st mask cover 171. FIG. FIG. 6B is an enlarged view of a part of the second mask cover 173. FIG. 10 is a third flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. FIG. (A) is the figure which expanded a part of 3rd mask cover 175. FIG. (B) is an enlarged view of a part of the fourth mask cover 177. (A) is the graph which showed the frequency temperature characteristic. (B) is a graph showing the relationship between the vertex temperature ZTC and the film thickness F4 of the second side surface layer in the first tuning-fork type piezoelectric vibrating piece 100. FIG. (C) is a graph showing the relationship between the vertex temperature ZTC and the film thickness F1 of the groove second layer 531 in the first tuning-fork type piezoelectric vibrating piece 100. (D) is a schematic sectional view of the right groove region 13R when the film thickness F4 of the side surface second layer 532 is reduced. (E) is a schematic sectional drawing of the right groove area | region 13R when the film thickness F4 of the side surface 2nd layer 532 is thickened. 6 is a flowchart for explaining a method of adjusting the vertex temperature ZTC of the tuning fork type piezoelectric vibrating piece 100. It is the figure which expanded a part of 5th mask cover 179. FIG. FIG. 4A is a plan view of a second tuning-fork type piezoelectric vibrating piece 200. FIG. FIG. 6B is a cross-sectional view of the second tuning-fork type piezoelectric vibrating piece 200 taken along the line GG. (C) is a cross-sectional view of the piezoelectric device 2000 as viewed in the −Z-axis direction. FIG. 6A is a plan view of a third tuning-fork type piezoelectric vibrating piece 300. FIG. (B) is the schematic sectional drawing which showed the state before assembling the piezoelectric device 3000 in the KK cross section of Fig.14 (a). FIG. 14C is a cross-sectional view of the third tuning-fork type piezoelectric vibrating piece 300 in the HH cross section of FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

<Configuration of First Tuning Fork Type Piezoelectric Vibrating Piece 100>
The first tuning-fork type piezoelectric vibrating piece 100 will be described with reference to FIG.
FIG. 1A is a plan view of the first tuning-fork type piezoelectric vibrating piece 100. 1B is a cross-sectional view of the first tuning-fork type piezoelectric vibrating piece 100 in the BB cross section of FIG. 1A, and FIG. 1C is a cross-sectional view of CC of FIG. FIG. 3 is a cross-sectional view of a first tuning-fork type piezoelectric vibrating piece 100 in a cross section. Hereinafter, the direction in which the vibrating arm 12 extends will be described as the Y-axis direction, the direction in which the pair of vibrating arms 12 are aligned will be described as the X-axis direction, and the direction orthogonal to the X-axis direction and the Y-axis direction will be described as the Z-axis direction.

  The first tuning-fork type piezoelectric vibrating piece 100 includes a base 11 and a pair of vibrating arms 12 extending from the base 11 in parallel to the Y-axis direction. The vibrating arm 12 has a front and back surface and both side surfaces that intersect on both sides of the front and back surface. The first tuning-fork type piezoelectric vibrating piece 100 has a piezoelectric material CR as a base material. For the piezoelectric material CR, crystal, lithium tantalate, lithium niobate or the like is used.

  The pair of vibrating arms 12 includes a groove region 13 having a groove portion 23 extending on the Y axis side on the −Y axis side and side surface portions 24 on both sides of the groove portion 23, and a weight region 19 having a weight function on the + Y axis side. The + X axis side of the pair of vibrating arms 12 is referred to as a right vibrating arm 12R, and the −X axis side is referred to as a left vibrating arm 12L. Similarly, the + X axis side of the groove region 13 is called a right groove region 13R and the −X axis side is called a left groove region 13L, the + X axis side of the groove portion 23 is called a right groove portion 23R, and the −X axis side is called a left groove portion 23L. The + X axis side of the weight region 19 is referred to as a right weight part 19R, and the −X axis side is referred to as a left weight part 19L.

  When the first tuning-fork type piezoelectric vibrating piece 100 is downsized, the vibration frequency tends to increase. The right weight part 19R and the left weight part 19L have a role of lowering the vibration frequency of the first tuning-fork type piezoelectric vibrating piece 100 and stabilizing the vibration of the vibrating arm 12. The right groove portion 23R and the left groove portion 23L are formed with excitation electrodes, which will be described later, and suppress an increase in CI value (crystal impedance value).

  A length L1 of the base portion 11 in the Y-axis direction is, for example, 0.58 mm to 0.64 mm. The length L2 of the vibrating arm 12 in the Y-axis direction is about 1.45 mm to 1.65 mm. Therefore, the length L1 of the base 11 with respect to the length L2 of the vibrating arm 12 is about 40 percent. The length L3 of the groove region 13 in the Y-axis direction is about 60% to 70% of the length L2 of the vibrating arm 12, and is formed from 0.87 mm to 1.12 mm.

  The length W1 of the base 11 in the X-axis direction is about 0.42 mm to 0.50 mm. A width W2 of the weight region 19 in the X-axis direction is about 0.08 mm to 0.12 mm. A distance W3 between the right groove region 13R and the left groove region 13L is about 0.1 mm to 0.15 mm. Further, the width W4 of the right groove portion 23R and the left groove portion 23L is about 0.07 mm to 0.1 mm, which is about 80% of the width of the vibrating arm 12.

  The thickness D1 of the first tuning-fork type piezoelectric vibrating piece 100 is about 0.08 mm to 0.12 mm. Further, the depth D2 of the groove region 13 on the + Z axis side and the −Z axis side is 30% to 45% of the thickness of the vibrating arm 12, and is 0.03 mm to 0.045 mm.

  In the first tuning-fork type piezoelectric vibrating piece 100, electrodes are formed on each of the base portion 11, the weight region 19, and the groove region 13. Since gold (Au) and silver (Ag) used as electrodes are difficult to form directly on the piezoelectric material CR, the first layer 15 made of Cr, Ni or the like is formed on the surface of the piezoelectric material CR in the same shape as the electrodes. The second layer (51, 531, 532, 59) made of gold, silver or the like is formed on the surface of the first layer 15. That is, the electrode is composed of the first layer 15 and the second layer (51, 531, 532, 59).

  The film thickness F3 (see FIG. 1C) of the first layer 15 is 50 to 200 mm. The thickness F3 of the first layer 15 is substantially the same in the base 11, the groove region 13, and the weight region 19. A difference may occur in the film thickness F3 of the first layer 15 depending on the shape of the piezoelectric material CR and the arrangement of the piezoelectric material CR in the vacuum evaporation apparatus or the sputtering apparatus. The film thickness F3 of the first layer 15 is preferably as thin as possible. The film thickness of the second layer (51, 531, 532) will be described later.

  An excitation electrode 53 is formed in the groove region 13. As shown in FIG. 1B, the excitation electrode 53 formed in the groove region 13 of each vibrating arm 12 is formed on the groove portion second layer 531 formed in the groove portion 23 and on the side surfaces of the + X axis and the −X axis. The side surface second layer 532 can be divided. A groove second layer 531R is formed in the right groove 23R, and a groove second layer 531L is formed in the left groove 23L. Further, the second side surface layer 532R is formed on the + X axis side surface and the −X axis side surface of the right groove region 13R, and the second side layer 532L is formed on the + X axis side surface and the −X axis side surface of the left groove region 13L. .

  A base second layer 51 is formed on the base 11, and the base second layer formed on the + X axis side of the base 11 is 51R, and the base second layer formed on the −X axis side is 51L. As shown in FIG. 1C, the base second layer 51R and the base second layer 51L are each formed from the surface on the + Z-axis side of the base 11 to the surface on the −Z-axis side through the side surface.

As shown in FIGS. 1A to 1C, the second layer formed on the first tuning-fork type piezoelectric vibrating piece 100 includes a base second layer 51R, a side surface second layer 532R, and a weight. The region second layer 59R and the groove second layer 531L are electrically connected. Further, the base second layer 51L, the side surface second layer 532L, the weight region second layer 59L, and the groove second layer 531R are electrically connected. 1A to 1C, hatching having the same pattern is drawn on the second layer having the same potential.
In the weight region 19, a weight region second layer 59 is formed, a weight region second layer 59R is formed in the right weight portion 19R, and a weight region second layer 59L is formed in the left weight portion 19L. .

  When the first tuning-fork type piezoelectric vibrating piece 100 is vibrated, a voltage is applied to the base second layer 51R and the base second layer 51L. When a voltage is applied, the first tuning-fork type piezoelectric vibrating piece 100 vibrates at a resonance frequency of 32.768 kHz, for example.

(Crystal impedance (CI value))
<Regarding the film thickness of the electrode>
As shown in FIG. 1B or FIG. 1C, the groove second layer 531 formed in the groove 23 of the vibrating arm 12 is formed with a film thickness F1, and the base second layer 51 is formed with a film thickness F2. The side surface second layer 532 is formed with a film thickness F4. Note that the thicknesses of the film thickness F1, the film thickness F2, and the film thickness F4 vary depending on the region depending on the situation of sputtering or vacuum deposition. For example, as shown in FIG. 1B, the groove 23 has a surface extending in the Z-axis direction and a surface in the X-axis direction. In sputtering or the like, the surface extending in the Z-axis direction of the groove portion 23 is easily formed with a thin film thickness F1, and the surface extending in the X-axis direction of the groove portion 23 is easily formed with a large film thickness F1. In this specification, the average thickness of the entire thickness of the groove second layer 531 is defined as a film thickness F1.

  The film thickness F2 of the base second layer 51 is formed to 500 to 2000 mm. The film thickness F2 of the base second layer 51 is preferably 500 mm or more. In the base second layer 51, the first tuning-fork type piezoelectric vibrating piece 100 is fixed to the connection terminal 74 (see FIGS. 3B and 3C) in the package 70. In order to ensure electrical connection between the base second layer 51 and the connection terminal 74, it is preferable that the film thickness F2 of the base second layer 51 is thick. When the film thickness F2 of the base second layer 51 is less than 500 mm, the electrical connection resistance increases and the CI value of the first tuning-fork type piezoelectric vibrating piece 100 increases. On the other hand, the thickness F2 of the base second layer 51 is preferably 2000 mm or less from the viewpoint of manufacturing cost.

  FIG. 2A is a graph showing the relationship between the CI value of the first tuning-fork type piezoelectric vibrating piece 100 and the film thickness of the groove second layer 531 / the film thickness of the base second layer 51 (F1 / F2). . In FIG. 2A, the film thickness F2 of the base second layer 51 is constant, and the value of F1 / F2 is changed by changing the film thickness F1 of the groove second layer 531 to measure the CI value. At this time, the thickness F4 of the second side layer 532 is constant.

  As shown in the graph of FIG. 2A, the CI value is the lowest when F1 / F2 is about 50%. If the film thickness F1 of the groove second layer 531 is larger than a predetermined thickness, the vibration of the piezoelectric material CR is hindered, and the CI value increases. Moreover, since the electrical resistance increases if the film thickness F1 of the groove second layer 531 is too thin, the CI value increases. When F1 / F2 is about 30 to 80%, the CI value is 60 kΩ or less, and a good CI value is obtained. Therefore, when the film thickness F2 of the base second layer 51 is 1000 mm, the film thickness F1 of the groove second layer 531 is preferably about 300 mm to 800 mm.

  Moreover, when the same measurement was performed by changing the film thickness F2 of the base second layer 51, the following results were obtained. When the film thickness F2 of the base second layer 51 is 500 mm, the film thickness F1 of the groove second layer 531 is preferably about 150 mm to 450 mm. This film thickness is 30% to 90% of the film thickness F2 of the base second layer 51. When the film thickness F2 of the base second layer 51 is 2000 mm, the film thickness F1 of the groove second layer 531 is preferably about 400 mm to 800 mm. This film thickness is 20% to 40% of the film thickness F2 of the base second layer 51. Therefore, when the film thickness F2 of the base second layer 51 is 500 to 2000 mm, the film thickness F1 of the groove second layer 531 is preferably 20% to 90% of the film thickness F2 of the base second layer 51.

  When a voltage is applied to the groove second layer 531, the weight region 19 of the vibrating arm 12 vibrates in the X-axis direction. At this time, if the film thickness F1 of the groove second layer 531 is large, vibration of the weight region 19 tends to be hindered. That is, when the thickness of the excitation electrode 53 is large, the influence on the vibration of the vibrating arm 12 is increased. Therefore, the thickness F1 of the groove second layer 531 is preferably thinner than the film thickness F2 of the base second layer 51. However, when the film thickness F1 of the groove second layer 531 is 20% or less of the film thickness F2 of the base second layer 51, the CI value is remarkably increased.

  FIG. 2B is a graph showing the relationship between the CI value of the first tuning-fork type piezoelectric vibrating piece 100 and the film thickness of the side surface second layer 532 / the film thickness of the base second layer 51 (F4 / F2). . In FIG. 2B, the film thickness F2 of the base second layer 51 is constant, and the value of F4 / F2 is changed by changing the film thickness F4 of the side surface second layer 532, and the CI value is measured. At this time, the film thickness F1 of the groove second layer 531 is constant. From the graph of FIG. 2B, it can be seen that the CI value does not change even when the thickness F4 of the side surface second layer 532 is changed.

  FIG. 2A shows that adjustment for lowering the CI value can be performed by adjusting the film thickness F <b> 1 of the groove second layer 531. In the adjustment for decreasing the CI value, only the film thickness F1 of the groove second layer 531 may be adjusted, or the film thickness F4 of the side surface second layer 532 is not related to the CI value (FIG. 2B). The thickness of the second layer in the entire groove region 12 including the thickness F1 of the groove second layer 531 and the thickness F4 of the side surface second layer 532 may be adjusted.

  As a method of reducing the film thickness in the adjustment of the film thickness of the second layer, dry etching using an inert gas such as argon, sublimation of a metal film by laser light irradiation, or metal etching using a resist as a mask, etc. It can be carried out. For example, FIG. 2C shows a photograph of the right groove region 13R from which part of the groove second layer 531R has been removed by laser light irradiation. In FIG. 2C, a plurality of regions 60 in which the metal film of the groove second layer 531R is sublimated by the laser beam are observed. When the film thickness is reduced by a method such as dry etching, laser light, or metal etching, the surface of the reduced film is formed into a rough surface. Further, the film thickness F4 of the second side layer 532R can be adjusted by the same method.

  As a method of increasing the film thickness in adjusting the film thickness of the second layer, a metal film can be additionally formed by a method such as sputtering or vacuum deposition. For example, FIG. 2D shows a cross-sectional view of the right groove region 13R in which the film thickness F4 of the second side layer 532R is increased by sputtering. In FIG. 2D, the side surface second layer 532Ra is first formed in the right groove region 13R, and the side surface second layer 532Rb is additionally formed on the surface of the side surface second layer 532Ra by sputtering. Finally, the second side layer 532R is formed. In FIG. 2D, a step 61 is formed at the boundary between the side surface second layer 532Ra and the side surface second layer 532Rb. The film thickness F1 of the groove second layer 531R can be adjusted by the same method.

  The adjustment of the film thickness as described above can be performed at the time of adjusting the CI value and the apex temperature ZTC described later. The CI value and the apex temperature ZTC are adjusted by the correspondence between the film thickness, the CI value and the apex temperature ZTC as shown in FIG. 2A and FIGS. 10B and 10C described later. It is desirable that the measurement is performed after a preferable film thickness is calculated based on the above data.

<Configuration of piezoelectric device 1000>
The piezoelectric device 1000 houses the first tuning fork type piezoelectric vibrating piece 100. The piezoelectric device 1000 will be described with reference to FIG. 3A is a perspective view of the piezoelectric device 1000, and FIG. 3B is a cross-sectional view of the piezoelectric device 1000 taken along the line EE in FIGS. 3A and 3C. 3 (c) is a cross-sectional view of the piezoelectric device 1000 in the FF cross section of FIG. 3 (b).

  The piezoelectric device 1000 includes a package 70, a lid 71, and a first tuning fork type piezoelectric vibrating piece 100. The package 70 is a concave box made of ceramics as a base material. The connection terminal 74 formed on the package 70 is electrically connected to an external terminal 75 formed on the outer surface of the package 70 through a conduction portion 76 formed in the wall of the package 70. The external terminal 75 is a terminal that is electrically connected to a printed circuit board (not shown) by solder or the like. The lid 71 is a metal plate that seals the package 70. The lid 71 and the package 70 are sealed with a sealing material 72.

  The first tuning fork type piezoelectric vibrating piece 100 is fixed in a cavity formed by the lid 71 and the package 70. A part of the base second layer 51 of the first tuning-fork type piezoelectric vibrating piece 100 serves as a connection electrode. The connection electrode is an electrode that is electrically connected to the connection terminal 74 formed on the inner surface of the package 70 via a conductive member such as a conductive adhesive 73 or solder. In the first tuning-fork type piezoelectric vibrating piece 100, a conductive adhesive 73 is applied to a partial region of the base second layer 51 and fixed on the connection terminal 74.

<Electrode formation flowchart of tuning fork type piezoelectric vibrating piece>
A plurality of methods are conceivable for forming the electrode of the first tuning-fork type piezoelectric vibrating piece 100. Hereinafter, a method of forming electrodes of the three first tuning-fork type piezoelectric vibrating pieces 100 will be described with reference to the first flowchart, the second flowchart, and the third flowchart.

  FIG. 4 is a first flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. FIG. 6A is a plan view of the piezoelectric material wafer 150 on which the first tuning-fork type piezoelectric vibrating piece 100 is formed, and FIG. 6B is a diagram showing an enlarged portion 160 of the piezoelectric material wafer 150. . FIG. 7A is an enlarged view of a part of the first mask cover 171, and FIG. 7B is an enlarged view of a part of the second mask cover 173. In FIG. 7, the outer shape of the first tuning-fork type piezoelectric vibrating piece 100 of the enlarged portion 160 of FIG. 6B is indicated by a dotted line.

An electrode forming process on the first tuning-fork type piezoelectric vibrating piece 100 will be described with reference to FIGS. 4, 6, and 7.
The first tuning-fork type piezoelectric vibrating piece 100 at the start of the flowchart of FIG. 4 is in the state of FIG. 6A in which the first tuning-fork type piezoelectric vibrating piece 100 is formed on the piezoelectric material wafer 150. As shown in FIG. 6B, the outer shape of the first tuning-fork type piezoelectric vibrating piece 100 having the groove 23 of the vibrating arm 12 is formed on the piezoelectric material wafer 150. The piezoelectric material wafer 150 is made of, for example, an artificial quartz having a thickness of 0.12 mm, and has a diameter of 3 inches or 4 inches. Further, an orientation flat 151 for specifying the crystal direction is formed on a part of the peripheral edge of the piezoelectric material wafer 150.

  In step S101, a metal film is formed on the entire piezoelectric material wafer 150 by a technique such as vapor deposition or sputtering. As the metal film, a metal film to be the first layer 15 (see FIGS. 1B and 1C) is formed on the piezoelectric material wafer 150, and a metal film to be the second layer on the first layer 15. Is formed. The metal film to be the second layer is formed with a thickness of about 400 mm, for example.

  In step S102, the first mask cover 171 or the second mask cover 173 is placed on the piezoelectric material wafer 150 on which the first layer and the second layer are formed. The first mask cover 171 or the second mask cover 173 is placed so as to be superimposed on the enlarged portion 160 of the piezoelectric material wafer 150 shown in FIG. When metal films are formed on both surfaces of the piezoelectric material wafer 150 at once, mask covers are placed on both surfaces.

  As shown in FIG. 7A, the region 231 of the first mask cover 171 is an open region, and the region 232 is a portion to be masked. The region 232 of the first mask cover 171 covers the groove region 13 of the first tuning-fork type piezoelectric vibrating piece 100 and prevents formation of a metal film on the groove region 13, and the region 231 is a stack of metal films on the base 11 and the weight region 19. Forgive. As shown in FIG. 7B, the region 236 of the second mask cover 173 is an open region, and the region 237 is a masked region. The region 237 of the second mask cover 173 covers the groove region 13 of the first tuning-fork type piezoelectric vibrating piece 100 and prevents formation of a metal film on the groove region 13, and the region 236 allows the base 11 to be laminated with a metal film.

  In step S103, a metal film is formed on the piezoelectric material wafer 150 by a technique such as sputtering. When the first mask cover 171 is placed, a metal film of, for example, 600 mm is laminated on the base 11 and the weight region 19 via the region 231 of the first mask cover 171. A metal film is not laminated in the groove region 13. If the second mask cover 173 is placed, a metal film of 600 mm, for example, is laminated on the base 11 via the region 236 of the second mask cover 173, and no metal film is laminated on the groove region 13. As a result of laminating the metal film using the first mask cover 171 or the second mask cover 173, the film thickness F1 of the groove second layer 531 in the groove region 13 is formed to be about 400 mm, and the base second layer 51 of the base 11 is formed. The film thickness F2 is about 1000 mm.

  In step S104, a photoresist is applied to the entire surface of the second layer by spraying or spin coating. Thereafter, the photoresist is cured.

  In step S105, a photomask (not shown) corresponding to the electrode pattern is prepared, and the electrode pattern is exposed to the piezoelectric material wafer 150 on which the photoresist film is formed. Since the electrode pattern needs to be formed on both surfaces of the first tuning-fork type piezoelectric vibrating piece 100, both surfaces of the piezoelectric material wafer 150 are exposed.

  In step S106, after the photoresist film is developed, the exposed photoresist film is removed. The remaining photoresist film becomes a photoresist film corresponding to the electrode pattern. Further, unnecessary metal films are removed by etching. For example, the metal used for the second layer is gold, and the metal used for the first layer 15 is chromium. Gold is etched with an aqueous solution of iodine and potassium iodide, and chromium is etched with an aqueous solution of ceric ammonium nitrate and acetic acid.

  In step S107, the photoresist on the piezoelectric material wafer 150 is removed. Through these steps, the first layer and the second layer are formed on the first tuning-fork type piezoelectric vibrating piece 100.

In step S108, the resonance frequency and CI value of the first tuning-fork type piezoelectric vibrating piece 100 on the piezoelectric material wafer 150 are measured. If the resonance frequency is not the target frequency, the weight region 19 is irradiated with laser light to sublimate the metal film and the frequency is adjusted.
In step S <b> 109, the first tuning-fork type piezoelectric vibrating piece 100 is cut from the piezoelectric material wafer 150.

  FIG. 5 is a second flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. An electrode forming process on the first tuning-fork type piezoelectric vibrating piece 100 will be described with reference to FIGS. 5 and 7B.

  In step S201, the first layer and the second layer are formed on the entire piezoelectric material wafer 150 by a technique such as vapor deposition or sputtering. The metal film to be the second layer is formed with a thickness of about 400 mm, for example.

In step S202, a photoresist is applied to the entire surface of the second layer.
In step S203, the electrode pattern is exposed to the piezoelectric material wafer 150 on which the photoresist film is formed.
In step S204, after developing the photoresist film, the exposed photoresist film is removed. Further, unnecessary metal films are removed by etching.
In step S205, the photoresist on the piezoelectric material wafer 150 is removed. Through these steps, the first layer and the second layer are formed on the first tuning-fork type piezoelectric vibrating piece 100.

  In step S206, the second mask cover 173 is placed on the piezoelectric material wafer 150 on which the first layer and the second layer are formed. The second mask cover 173 is placed so as to be overlaid on the enlarged portion 160 of the piezoelectric material wafer 150 shown in FIG.

  As shown in FIG. 7B, one opening region 236 of the second mask cover 173 has a base second layer 51R of one first tuning fork type piezoelectric vibrating piece 100 and an adjacent first tuning fork type piezoelectric vibration. The metal film can be stacked on the base second layer 51L (see FIG. 1) of the piece 100.

  In step S207, a metal film is formed on the piezoelectric material wafer 150 by a technique such as sputtering. Through the region 236 of the second mask cover 173, for example, a 600-mm metal film is laminated on the base second layer 51R and the second layer 51L. A metal film is not formed between the base second layer 51R and the second layer 51L of one first tuning-fork type piezoelectric vibrating piece 100, and there is no short circuit. As a result of laminating the metal film using the second mask cover 173, the film thickness F1 of the groove second layer 531 in the groove region 13 is formed to about 400 mm, and the film thickness F2 of the base second layer 51 of the base 11 is 1000 mm. Formed to a degree.

In step S208, the resonance frequency and CI value of the first tuning-fork type piezoelectric vibrating piece 100 on the piezoelectric material wafer 150 are measured and adjusted.
In step S209, the first tuning-fork type piezoelectric vibrating piece 100 is cut from the piezoelectric material wafer 150.

  FIG. 8 is a third flowchart of electrode formation of the first tuning-fork type piezoelectric vibrating piece 100. An electrode forming process on the first tuning-fork type piezoelectric vibrating piece 100 will be described with reference to FIGS. FIG. 9A is an enlarged view of a part of the third mask cover 175 for etching, and FIG. 9B is an enlarged view of a part of the fourth mask cover 177 for etching. In FIG. 9, the outer shape of the first tuning-fork type piezoelectric vibrating piece 100 of the enlarged portion 160 in FIG. 6B is indicated by a dotted line.

  In step S301, a metal film is formed on the entire piezoelectric material wafer 150 by a technique such as vapor deposition or sputtering. The metal film to be the second layer is formed with a thickness of about 1000 mm, for example.

In step S302, a photoresist is applied to the entire surface of the second layer.
In step S303, the electrode pattern is exposed to the piezoelectric material wafer 150 on which the photoresist film is formed.
In step S304, after the photoresist film is developed, the exposed photoresist film is removed. Further, unnecessary metal films are removed by etching.
In step S305, the photoresist on the piezoelectric material wafer 150 is removed. Through these steps, the first layer and the second layer are formed on the first tuning-fork type piezoelectric vibrating piece 100.

  In step S306, the third mask cover 175 or the fourth mask cover 177 is placed on the piezoelectric material wafer 150 on which the first layer and the second layer are formed. The 3rd mask cover 175 or the 4th mask cover 177 is mounted so that it may overlap with the enlarged part 160 of the piezoelectric material wafer 150 shown in FIG.6 (b).

  As shown in FIG. 9A, the region 233 of the third mask cover 175 is an open region, and the region 234 is a masked region. The region 234 of the third mask cover 175 covers the weight region 19 and the base portion 11 of the first tuning-fork type piezoelectric vibrating piece 100 and prevents the metal film of the weight region 19 and the base portion 11 from being thinned. The metal film of the layer 531 and the side surface second layer 532 (see FIG. 1) is allowed to be thinned. As shown in FIG. 9B, the region 238 of the fourth mask cover 177 is an open region, and the region 239 is a masked region. A region 239 of the fourth mask cover 177 covers the weight region 19, the base portion 11, and the side surface portion 24 (see FIG. 1) of the first tuning fork type piezoelectric vibrating piece 100, and the metal film of the weight region 19, the base portion 11, and the side surface portion 24. The region 238 allows the metal film of only the groove second layer 531 to be thinned.

  In step S307, the metal film in the groove region 13 or the groove portion 23 is thinned by dry etching using an inert gas such as argon. As a result of thinning the metal film using the third mask cover 175 or the fourth mask cover 177, the film thickness F1 of the groove second layer 531 (see FIG. 1) in the groove region 13 is formed to be about 400 mm, for example. When the third mask cover 175 is used, the film thickness F4 of the side surface second layer 532 (see FIG. 1) is also reduced, for example, about 400 mm.

In step S308, the resonance frequency and CI value of the first tuning-fork type piezoelectric vibrating piece 100 on the piezoelectric material wafer 150 are measured and adjusted.
In step S <b> 309, the first tuning-fork type piezoelectric vibrating piece 100 is cut from the piezoelectric material wafer 150.
In the third flowchart, the film thickness F1 of the groove second layer 531 or the film thickness F4 of the side surface second layer 532 may be reduced by laser irradiation instead of dry etching.

(For the apex temperature ZTC)
<Adjustment of film thickness F4 of the second side layer>
Next, the adjustment of the vertex temperature ZTC of the first tuning fork type piezoelectric vibrating piece 100 will be described. By repeating the experiment, it was found that the vertex temperature ZTC was related to the film thickness F1 of the groove second layer 531 and the film thickness F4 of the side surface second layer 532.

  FIG. 10A is a graph showing frequency temperature characteristics of the first tuning-fork type piezoelectric vibrating piece 100. FIG. 10B is a graph showing the relationship between the vertex temperature ZTC and the film thickness F4 of the side surface second layer 532 in the first tuning-fork type piezoelectric vibrating piece 100. FIG. 10C is a graph showing the relationship between the vertex temperature ZTC and the film thickness F1 of the groove second layer 531 in the first tuning-fork type piezoelectric vibrating piece 100. FIG. 10D is a schematic cross-sectional view of the right groove region 13R when the thickness F4 of the second side layer 532 is reduced, and FIG. 10E is the case where the thickness F4 of the second side layer 532 is increased. It is a schematic sectional drawing of 13 R of right groove area | regions.

  As shown in FIG. 10A, the frequency of the first tuning-fork type piezoelectric vibrating piece 100 becomes a parabolic quadratic curve due to temperature change. The apex temperature ZTC is a temperature at which the frequency of the first tuning-fork type piezoelectric vibrating piece 100 is highest. In FIG. 10A, the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 indicates about 20 ° C.

  As shown in FIG. 10B, the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 also changes as the film thickness F4 of the side surface second layer 532 changes. When the film thickness F4 of the second side layer 532 of the first tuning fork type piezoelectric vibrating piece 100 was 750 mm, the vertex temperature ZTC of the first tuning fork type piezoelectric vibrating piece 100 was about 20 ° C. As shown in FIG. 10D, when the film thickness F4 of the second side layer 532 of the first tuning fork type piezoelectric vibrating piece 100 is reduced to 500 mm, the vertex temperature ZTC of the first tuning fork type piezoelectric vibrating piece 100 is about 25 ° C. there were. On the other hand, when the film thickness F4 of the side surface second layer 532 of the first tuning fork type piezoelectric vibrating piece 100 is increased to 1000 mm as shown in FIG. 10E, the vertex temperature ZTC of the first tuning fork type piezoelectric vibrating piece 100 is about 18. ° C. That is, when the film thickness F4 of the side surface second layer 532 is reduced, the vertex temperature ZTC can be increased, and when the film thickness F4 of the side surface second layer 532 is increased, the vertex temperature ZTC can be decreased. In addition, the measurement of the vertex temperature ZTC of the graph of FIG.10 (b) was performed by fixing the film thickness F2 of a base 2nd layer as 800 mm, and changing the film thickness F4 of the side surface 2nd layer 532. FIG. In FIG. 10B, the measurement is performed with the film thickness F1 of the groove second layer 531 being constant.

  As shown in FIG. 10C, the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 is expressed as a parabolic quadratic curve with respect to the change in the film thickness F1 of the groove second layer 531. When the film thickness F1 of the groove second layer 531 is MF1, the peak temperature ZTC takes the maximum value MZTC, and the peak temperature ZTC decreases as the film thickness F1 of the groove second layer 531 increases from MF1.

  The peak temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 may be deviated due to a cut angle shift of the piezoelectric material wafer 150, a variation in the shape of the first tuning-fork type piezoelectric vibrating piece 100, or the like. Even in such a case, the value of the vertex temperature ZTC can be adjusted by adjusting the film thickness F1 of the groove second layer 531 or the film thickness F4 of the side surface second layer 532. Further, as shown in FIG. 2B, the film thickness F4 of the side surface second layer 532 does not affect the CI value. Therefore, when it is desired to adjust only the apex temperature ZTC, the film thickness F4 of the side surface second layer 532 is set. It is more preferable to adjust.

<Adjustment flow chart of vertex temperature ZTC>
The vertex temperature ZTC of each first tuning-fork type piezoelectric vibrating piece 100 on the piezoelectric material wafer 150 is measured, and the vertex temperature ZTC is adjusted. FIG. 11 is a flowchart for explaining a method for adjusting the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100.

  The apex temperature ZTC is adjusted, for example, between step S108 and step S109 in the first flowchart of electrode formation shown in FIG. Similarly, it may be performed between step S208 and step S209 in the second flowchart in FIG. 5 or between step S308 and step S309 in the third flowchart in FIG.

In step S501, the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 formed on the piezoelectric material wafer 150 is measured.
Next, in step S502, it is determined whether or not the vertex temperature ZTC is different from the target temperature. The target temperature is appropriately determined depending on the environment in which the first tuning fork type piezoelectric vibrating piece 100 is used. This is because the change in frequency becomes the smallest with respect to the change in the use environment temperature in the vicinity of the vertex temperature ZTC. The target temperature is set at 25 ° C., for example. When the apex temperature ZTC is equal to the target temperature, the process proceeds to step S109 (see FIG. 4), step S209 (see FIG. 5) or step S309 (see FIG. 8). If the apex temperature ZTC is different from the target temperature, the process proceeds to step S503.

  In step S503, it is determined whether or not the vertex temperature ZTC is higher than the target temperature. If the vertex temperature ZTC is higher than the target temperature, the process proceeds to step S504, and if it is low, the process proceeds to step S505.

  In step S504, a metal film is formed on the side surface second layer 532 by vacuum evaporation or sputtering using the fifth mask cover 179 shown in FIG. The fifth mask cover 179 has a shape in which the surface on the Z-axis side of the first tuning-fork type piezoelectric vibrating piece 100 is taken. The fifth mask cover 179 is placed so as to be superimposed on the enlarged portion 160 of the piezoelectric material wafer 150 shown in FIG. Therefore, when the fifth mask cover 179 is used, the main surface of the first tuning fork type piezoelectric vibrating piece 100 can be covered, and the metal film can be laminated only on the side surface second layer 532.

  In order to determine the lamination thickness of the metal film, graphs as shown in FIG. 10B are prepared, and from these graphs, the relationship between the vertex temperature ZTC and the film thickness F4 of the side surface second layer 532 is the most. The formation amount of the metal film is determined with reference to a near graph. For example, when the apex temperature ZTC is 26 ° C., when setting the target temperature at 25 ° C., the film thickness F4 of the side surface second layer is laminated by about 50 mm from FIG.

  In step S505, the second side layer 532 is dry-etched with an inert gas such as argon using the fifth mask cover 179 shown in FIG. By using the fifth mask cover 179, only the side surface second layer 532 can be made thin without affecting the main surface of the first tuning-fork type piezoelectric vibrating piece 100.

  In step S506, the vertex temperature ZTC of the first tuning-fork type piezoelectric vibrating piece 100 is confirmed. In step S507, it is determined whether or not the vertex temperature ZTC is different from the target temperature. If the vertex temperature ZTC is different from the target temperature, the process returns to step S503 to readjust the vertex temperature ZTC. If the apex temperature ZTC is equal to the target temperature, the process proceeds to step S109 (see FIG. 4), step S209 (see FIG. 5), or step S309 (see FIG. 8).

<Regarding Second Tuning Fork Type Piezoelectric Vibrating Piece 200>
Even if the tuning fork type piezoelectric vibrating piece has a shape different from that of the first tuning fork type piezoelectric vibrating piece 100, the second groove layer may be thickened to reduce the CI value. Further, the thickness of the second side layer can be adjusted to adjust the apex temperature ZTC.

<Second Tuning Fork Type Piezoelectric Vibrating Piece 200>
FIG. 13A is a plan view of the second tuning-fork type piezoelectric vibrating piece 200. The second tuning-fork type piezoelectric vibrating piece 200 includes a base 11 and a pair of vibrating arms 12 extending in parallel to the Y-axis direction from the base 11, and further a pair of extending in the Y-axis direction on both outer sides of the pair of vibrating arms 12. Support arms 86 (86R, 86L) are provided.

  A support arm electrode second layer 85R is formed on the support arm 86R located on the + X axis side, and a support arm electrode second layer 85L is formed on the support arm 86L located on the −X axis side. The support arm electrode second layer 85R and the support arm electrode second layer 85L are formed from the base 11 to the vicinity of the tip of the support arm 86 in the + Y-axis direction. The support arm electrode second layer 85R and the support arm electrode second layer 85L are connected to the base second layer 51 extending from the excitation electrode. The tip region of the support arm electrode second layer 85 of the second tuning-fork type piezoelectric vibrating piece 200 serves as a connection electrode. The connection electrode is an electrode that is electrically connected via a conductive member such as a conductive adhesive 73 or solder formed on the inner surface of the package 80 (see FIG. 13C).

  FIG. 13B is a cross-sectional view of the piezoelectric vibrating piece 200 in FIG. Similar to the first tuning-fork type piezoelectric vibrating piece 100, by forming the film thickness F5 of the tip region of the support arm electrode second layer 85 to be larger than the film thickness F6 of the groove second layer and the film thickness F7 of the side surface second layer. , CI value can be kept low. The film thickness F5 of the tip region of the support arm electrode second layer 85 is preferably 500 to 2000 mm, and the film thickness F6 of the groove second layer and the film thickness F7 of the second side layer are preferably about 300 to 800 mm.

  The thickness of the region excluding the tip region of the support arm electrode second layer 85 may be as thin as the thickness F6 of the groove second layer or the thickness F7 of the side surface second layer, or the film of the tip region. It may be the same thickness as the thickness F5. The base second layer 51 of the second tuning-fork type piezoelectric vibrating piece 200 may be made as thin as the film thickness F6 of the groove second layer or the film thickness F7 of the side surface second layer, The same thickness may be used.

  Also, in the case of the second tuning fork type piezoelectric vibrating piece 200, similarly to the first tuning fork type piezoelectric vibrating piece 100, the vertex temperature is adjusted by adjusting the film thickness F 7 of the second side surface of the second tuning fork type piezoelectric vibrating piece 200. ZTC can be adjusted.

  FIG. 13C is a cross-sectional view of the piezoelectric device 2000 as viewed in the −Z axis direction. The piezoelectric device 2000 includes a second tuning fork type piezoelectric vibrating piece 200. The second tuning-fork type piezoelectric oscillation piece 200 is fixed to the package 80 of the piezoelectric device 2000 by the conductive adhesive 73 applied to the support arm 86R and the connection electrode 87 formed near the tip of the support arm 86L on the + Y-axis side. Are electrically connected. By connecting the second tuning-fork type piezoelectric vibrating piece 200 to the package 80 with the support arm 86, it is possible to place a distance between the fixed portion of the package 80 and the vibrating arm 12. Therefore, ambient temperature changes, drop impacts, stress changes generated at the joints, and the like are less likely to affect the vibrating arm 12. Therefore, the second tuning fork type piezoelectric vibrating piece 200 has better temperature characteristics and the like than the first tuning fork type piezoelectric vibrating piece 100.

<Regarding Third Tuning Fork Type Piezoelectric Vibrating Piece 300>
Even in a tuning fork type piezoelectric vibrating piece that is not housed in the ceramic package, the thickness of the second side layer can be adjusted to adjust the vertex temperature ZTC.

  FIG. 14A is a plan view of the third tuning-fork type piezoelectric vibrating piece 300. The third tuning-fork type piezoelectric vibrating piece 300 includes a pair of vibrating arms 12 extending in parallel with each other from the base portion 11, a pair of support arms 306 extending in the Y-axis direction, and a piezoelectric vibrating piece outer frame portion 310. ing. A pair of support arms 306 extending in the Y-axis direction connect the piezoelectric vibrating piece outer frame portion 310 and the base portion 11. The piezoelectric vibrating reed outer frame portion 310 is a frame that surrounds the base portion 11, the vibrating arm 12, and the support arm 306 inside. The piezoelectric vibrating reed outer frame portion 310 is joined to the lid 90 and the base 120 shown in FIG.

  An electrode is formed from the excitation electrode 307 formed on the vibrating arm 12 to the piezoelectric vibrating piece outer frame portion 310. Similar to the first tuning-fork type piezoelectric vibrating piece 100, this electrode includes an electrode first layer 15 formed on a piezoelectric material and an electrode second layer 311 formed on the electrode first layer 15. In the second electrode layer 311, the second electrode layer 311 </ b> R is disposed on the + X axis side, and the second electrode layer 311 </ b> L is disposed on the −X axis side. The terminal portions of the electrode second layer 311R and the electrode second layer 311L located at the corners of the piezoelectric vibrating piece outer frame portion 310 serve as connection electrodes.

  FIG. 14B is a schematic cross-sectional view showing a state before assembling the piezoelectric device 3000 in the KK cross section of FIG. The piezoelectric device 3000 includes a lid 90, a base 120, and a third tuning fork type piezoelectric vibrating piece 300. A lid 90 is disposed on the + Z-axis side of the piezoelectric device 3000, and a lid-side recess 91 is formed on the surface of the lid 90 on the −Z-axis side. A base 120 is disposed on the −Z axis side of the piezoelectric device 3000, and a base side recess 121 is formed on the surface of the base 120 on the + Z axis side. Recessed step portions 129 are provided at two corners located on the diagonal of the surface on the + Z-axis side of the base 120, and connection terminals 122 are disposed in the recessed step portions 129. Further, two external terminals 125 are provided on the surface of the base 120 on the −Z axis side. The connection terminal 122 and the external terminal 125 are electrically connected through the through hole 123. The third tuning-fork type piezoelectric vibrating piece 300 is disposed between the lid 90 and the base 120.

  The connection electrode 317 formed on the third tuning-fork type piezoelectric vibrating piece 300 is electrically connected to the connection terminal 122 formed on the base 120 and is externally connected through the conduction portion 126 formed in the through hole 123. It is electrically connected to the terminal 125. The piezoelectric device 3000 has a space formed by the lid-side recess 91 and the base-side recess 121, so that the lid 90 or the third tuning-fork-type piezoelectric vibrating piece 300 can vibrate even if the vibrating arm 12 vibrates in the Z-axis direction. The configuration is such that it does not contact the base 120.

  For example, the lid 90, the base 120, and the third tuning-fork type piezoelectric vibrating piece 300 are formed using quartz as a base material. In that case, the bonding of the lid 90, the base 120, and the third tuning-fork type piezoelectric vibrating piece 300 is performed by a siloxane bond (Si—O—Si) technique. The siloxane bonding technique is a technique for directly bonding crystals to each other and does not require the use of a sealing material. Further, the electrode second layer 311 and the connection terminal 122 are directly connected without using a conductive adhesive.

  FIG. 14C is a cross-sectional view of the third tuning-fork type piezoelectric vibrating piece 300 in the HH cross section of FIG. The vibrating arm 12 has the same shape as the vibrating arm 12 of the first tuning-fork type piezoelectric vibrating piece 100. A support arm 306 is positioned outside the vibrating arm 12, and a piezoelectric vibrating piece outer frame 310 is positioned outside the support arm 306. Similarly to the first tuning fork type piezoelectric vibrating piece 100, the third tuning fork type piezoelectric vibrating piece 300 is adjusted by adjusting the thickness F8 of the side surface second layer 316 of the vibrating arm 12. The apex temperature ZTC can be adjusted.

  The optimum embodiment of the present invention has been described in detail above. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

DESCRIPTION OF SYMBOLS 11 Base 12 Vibrating arm 13 Groove area | region 15 1st layer 19 Weight area | region 23 Groove part 24 Side surface part 51 Base 2nd layer 53,307 Excitation electrode 59 Weight area | region 2nd layer 70, 80 Package 71 Lid 72 Sealing material 73 Conductive adhesion Agent 74, 122 Connection terminal 75, 125 External terminal 76 Conductive part 86, 306 Support arm 90 Lid 91 Lid side concave part 100, 200, 300 Tuning fork type piezoelectric vibrating piece 120 Base 121 Base side concave part 123 Through hole 126 Conductive part 129 Concave type step Part 150 Piezoelectric material wafer 151 Orientation flat 160 Enlarged part of the piezoelectric material wafer 150 171 1st mask cover, 173 2nd mask cover, 175 3rd mask cover, 177 4th mask cover, 179 5th mask cover 231 1st mask cover 171 region 310 Piezoelectric vibrating piece outer frame portion 531 Groove portion second layer, 531L Groove portion second layer formed in left groove portion 23L, 531R Groove portion second layer formed in right groove portion 23R 532 Side surface second layer, 532L In groove region 13L Side surface second layer, 532R Side surface second layer in groove region 13R 1000, 2000, 3000 Piezoelectric device CR Piezoelectric material D1 Thickness of first tuning-fork type piezoelectric vibrating piece 100 D2 Depth of groove region 13 F1 Groove portion second layer 531 Film thickness of F2 base second layer 51 F3 Film thickness of first layer 15 F4 Film thickness of side surface second layer 532 L1 Length of base 11 in Y axis direction L2 Length of vibrating arm 12 in Y axis direction L3 Length in the Y-axis direction of the groove region 13 W1 Length in the X-axis direction of the base 11 W2 Width in the X-axis direction of the weight region 19 W3 The right groove region 13R of the right vibrating arm 12R and the left groove of the left vibrating arm 12L Distance to region 13L W4 right groove portion 23R and the width of the left groove portion 23L

Claims (13)

A tuning fork type piezoelectric vibrating piece fixed with a conductive member in a package,
A connection electrode electrically connected to the conductive member;
A pair of vibrating arms extending in a predetermined direction from a base made of a piezoelectric material and formed with excitation electrodes that are electrically connected to the connection electrodes;
The vibrating arm has front and back surfaces and both side surfaces that intersect on both sides of the front and back surfaces,
Grooves extending in a predetermined direction are formed on the front and back surfaces,
The excitation electrode has front and back electrodes formed in the groove portions of the front and back surfaces, and side electrodes formed on the both side surfaces, respectively.
The tuning fork type piezoelectric vibrating piece is thinner than the connection electrode.   The connection electrode and the excitation electrode include a first layer formed on the piezoelectric material and a second layer formed on the first layer, and the second layer of the front and back electrodes is formed of the connection electrode. The tuning-fork type piezoelectric vibrating piece according to claim 1, which is thinner than the second layer.   3. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein a film thickness of the front and back electrodes is 20 to 90% of a film thickness of the connection electrode.   4. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein the connection electrode is formed on the base portion. 5. A pair of support arms extending in the predetermined direction from the base on both outer sides of the pair of vibrating arms;
4. The tuning fork type piezoelectric vibrating piece according to claim 1, wherein the connection electrode is formed at a tip of the support arm. 5.   6. The tuning fork type piezoelectric vibrating piece according to claim 1, wherein the front and back electrodes are formed thin by etching with an inert gas, laser irradiation, or metal etching. A tuning fork type piezoelectric vibrating piece fixed in a package,
A pair of vibrating arms extending in a predetermined direction from a base portion made of a piezoelectric material and having front and back surfaces and both side surfaces intersecting the front and back surfaces on both sides;
An excitation electrode having front and back electrodes formed on the front and back surfaces and side electrodes respectively formed on the both side surfaces;
Based on the data of the correspondence between the film thickness of the side electrode or the film thickness of the front and back electrodes and the apex temperature of the frequency temperature characteristic, the apex temperature of the frequency temperature characteristic becomes the desired temperature for the film thickness of the side electrode. A tuning fork type piezoelectric vibrating piece in which a step or a rough surface is formed on the side electrode or the front and back electrodes.   The tuning fork type piezoelectric vibrating piece according to claim 7, wherein when the apex temperature is higher than the desired temperature, the film thickness of the side electrode or the front and back electrodes is increased.   The tuning-fork type piezoelectric vibrating piece according to claim 8, wherein the side electrode or the front and back electrodes are formed thick by sputtering or vacuum deposition.   The tuning fork type piezoelectric vibrating piece according to claim 7, wherein when the apex temperature is lower than the desired temperature, the film thickness of the side electrode or the front and back electrodes is reduced.   11. The tuning fork type piezoelectric vibrating piece according to claim 10, wherein the side electrode or the front and back electrodes are formed thin by etching with an inert gas, laser irradiation, or metal etching.   The excitation electrode includes a first layer formed on the piezoelectric material and a second layer formed on the first layer, and a film thickness of the second layer of the side electrode or the front and back electrodes is adjusted. The tuning fork type piezoelectric vibrating piece according to any one of claims 7 to 11. A tuning-fork type piezoelectric vibrating piece according to any one of claims 1 to 12,
A package for housing the tuning-fork type piezoelectric vibrating piece;
A piezoelectric device characterized by comprising: